I really have trouble believing that thing is solid. I mean, I've got an whole construction welded together, and even that isn't exactly rock solid.I had the same problem so I bought me a wheelstandpro. Now I can play from my couch/seat without a problem. It's very sturdy and works very well.
So that's why every video of GT5 builds (at PD's Office or at any gameshow) is full is Driving Force GT's?I think you'll find that GT is specifically designed to be played with the pad. Wheel support is secondary.